When investigators searched the suspect’s home in the western town of Toenisvorst they not only found evidence he had betrayed secrets, but also discovered pornography featuring the 51-year-old man, tabloid Bild wrote.

The Bundesverfassungsschutz (BfV) intelligence agency declined to comment on the report because of the ongoing investigation. It has said the man was arrested after making Islamist statements on the Internet and offering to share sensitive data about the spy agency’s work in chatrooms. [nL8N1DU6FA].

The BfV defended its security checks after the arrest, saying that the man had behaved completely inconspicuously.

Even his family obviously knew nothing about his double life including his alleged conversion to Islam, a security source told Reuters on Thursday.

Conservative politicians demanded more frequent security checks to avoid similar problems in future.

“We should have a security check once a year instead of every few years,” Patrick Sensburg of the ruling CDU party said in an interview with the daily Handelsblatt.

The suspect, who remains in custody, was hired in April and played only a minor role in the agency, being tasked with the observation of Islamists, the security source said.

Before joining the service, he had been working as sales manager of a bank. Data found on the Internet by Reuters showed he had also been active in voluntary work and local politics, and was one of two proprietors of a tattoo shop.

It remained unclear if the suspect actually did damage while working for the spy agency and if he was in touch with radical Islamists at all, the source said. “There have to be investigations on whether he passed on information - and if and to what extent there was a connection to the Islamist scene.”

It is not known if the suspect had contact with a suspected Islamist from the same town known by the alias Abu Walaa, who was arrested in November and is described by security authorities as a leading Islamist ideologist in Germany.

Authorities have ramped up their surveillance of suspected Islamist individuals and groups after two attacks claimed by Islamic State in July.